Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF)

Link State Algorithm Sends Update when it occurs only, link state protocols deal with three types of tables, they are: Neighbors table Topology table Route table

Open Shortest Path First (OSPF) Allows multi-vendor deployment (Open standard) R.P Link state R.P Classless R.P Supports VLSM and discontiguous networks Has unlimited hop count Does not make auto-summery (because of using wildcard) AD = 110 “O” in Route Table Used within one autonomous system (AS 1~65535) Used with areas (2^32) Supports authentication Fast convergence

/ / /24 Router(config)#router ospf 10 (local significant) Router(config-router)#network area 1 Router(config-router)#network area 1 Router(config-router)#network area 0

OSPF Terminology Link Router ID RID Neighbor Router Adjacent Router Designated Router DR Backup Designated Router BDR Hello protocol Link State Advertisement LSA Neighborship database Topological database OSPF areas DR BDR R2 R3R4 R1

Why will we use areas? I.Fast building routing table II.Decreasing overload on router III.Simpler troubleshooting Hierarchical Design (Areas)

Neighbors table is constructed using Hello packets LSA Packets are transmitted between routers to construct Topological database Shortest path tree is constructed Dijkstra or SPF algorithm to find best for destinations with multiple paths Results go to the route table

Network Types with OSPF 1- Point to Point Hello interval= 10 sec. Dead interval= 40 sec. 2- Point-to-multipoint Hello interval= 10 sec. Dead interval= 40 sec. 3- Broadcast (multi-access) Hello interval= 10 sec. Dead interval= 40 sec. 4- Non-broadcast multi-access NBMA (Frame-Relay or X.25) Hello interval= 30 sec. Dead interval= 120 sec.

Electing DR and BDR 1- Priority (0~255); 1 by default 2- Router ID: Router(config)#int loopback 0 Router(config-if)#ip add Router(config-if)#no shut If there is only physical interface If there is loopback interface

OSPF Metric Metric= cost= (10^8/B.W in bps) Fast Ethernet= 100Mbps Cost= 10^8/(100x10^6) =1 Ethernet= 10Mbps Cost= 10^8/(10x10^6) =10 Serial= 1.54Mbps Cost= 10^8/( ^6) =64 Router(config)#int s0 Router(config-if)#ip ospf hello-interval 40 Router(config-if)#ip ospf dead-interval 160 Router(config-if)#ip ospf priority 25 Router(config-if)#ip ospf cost 20

Show Commands Router#sh ip ospf (Process ID, Area ID, RID, SPF statistics, and LSA timer information) Router#sh ip ospf database (Process ID, Area ID, RID, Topology Table) Router#sh ip ospf interface (Process ID, Area ID, RID, Interface IP address, Network type, Cost, Priority, DR/BDR election information (if applicable), Hello and Dead timer intervals, Adjacent neighbor information ) Router#sh ip ospf neighbor (Process ID, Area ID, RID, Neighbors table, DR/BDR information) DR/BDR Information Full/ Full/DR Full/BDR Full/2 way DR other

Debugging OSPF Router#debug ip ospf packet Router#debug ip ospf hello Router#debug ip ospf adj

Manual Summarization / / / / / / / A1700B2600A B.2 f0.2 f0.1 s0.1 s1.1 s0/0.2 s0/0.2 s0.2 s0/1.1 f0/0.1 f0/0.1 e0.1 Area 1Area 0

Manual Summarization In Router 2600A 2600A(config)#router ospf A(config-router)#network area A(config-router)#network area A(config-router)#network area A(config-router)#area 1 range

Enhanced Interior Gateway Routing Protocol (EIGRP) Cisco Proprietary R.P Hybrid (advanced distance-vector) R.P Classless R.P Supports VLSM and discontiguous networks Max. hops 255 (100 by default) Makes auto-summery by default, auto-summery can be disabled Use composite metric (B.W, Reliability, Delay, Load, MTU) AD = 90 (for internal EIGRP route), AD = 170 (for external EIGRP route) “D” in Route Table Used within one autonomous system (AS 1~65535) Best path selection via Diffusing Update Algorithm (DUAL) The only R.P that supports for IP, IPv6, IPX, and Apple Talk via protocol dependent modules (PDM) Communication via Reliable Transport Protocol (RTP)

EIGRP Packets 1- Hello Packet 2- Update Packet 3- Query Packet 4- Reply Packet 5- Acknowledge Packet 1- Hello Packet Multicast each (5 sec), holddown (15 sec) 2- Update Packet Neighbors Table My Int.Neg. IP Topology Table Path1 SuccNet1 Path2 F.SuccNet1 Path3 F.SuccNet1 Path1 SuccNet2 Path2 F.SuccNet2 Path1 SuccNet3 Routing Table Path1 SuccNet1 Path1 SuccNet2 Path1 SuccNet3 DUAL Alg.

Next Hop R.D= Reported Distance Next Hop R.D= Reported Distance F.D= Feasible Distance F.D= Next Hop + R.D F.D of Succ. > R.D of F. Succ (New Succ)

3- Query Packet Holddown (180 sec), (16 x 5 sec) 4- Reply Packet 5- Acknowledge Packet / / /24 Router(config)#router eigrp 10 (AS) Router(config-router)#network Router(config-router)#network Router(config-router)#no auto-summery

Variance Vector New Best Path ≤ Variance x Old Best Path Topology Table 1000Path1 SuccNet1 1500Path2 F.SuccNet1 2000Path3 F.SuccNet1 3000Path4 F.SuccNet1 New Best Path ≤ 2 x 1000 New Best Path ≤ 2000 Topology Table 1000Path1 SuccNet1 1500Path2 F.SuccNet1 2000Path3 F.SuccNet1 3000Path4 F.SuccNet1 Router(config)#eigrp 10 Router(config-router)#variance 2 Router(config-router)#maximum-paths 6

Manual Summarization / / / / / / / A1700B2600A B.2 f0.2 f0.1 s0.1 s1.1 s0/0.2 s0/0.2 s0.2 s0/1.1 f0/0.1 f0/0.1 e0.1 IGRPEIGRP Automatic Redistribution EIGRP with IGRP

/ / / / / / / A1700B2600A B.2 f0.2 f0.1 s0.1 s1.1 s0/0.2 s0/0.2 s0.2 s0/1.1 f0/0.1 f0/0.1 e0.1 Manual Summarization

2600A(config)#router eigrp A(config-router)#network A(config-router)#network A(config-router)#no auto-summery 2600A(config-router)#exit 2600A(config)#int s0/1 2600A(config-if)#ip summary-address eigrp

Show and Debugging Commands Router#sh ip eigrp neighbor Router#sh ip eigrp topology Router#sh ip route Router#sh ip route rip Router#sh ip route igrp Router#sh ip route ospf Router#sh ip route eigrp Router#debug eigrp packet Router#debug ip eigrp notification Router#clear ip route *